The present invention relates to double-diaphragm pumps and particularly to valves that direct the flow of pressurized air to air chambers of double-diaphragm pumps. Conventional double-diaphragm pumps include two diaphragms, one coupled to each end of a connecting rod. Pressurized air is alternately pumped into and evacuated from air chambers created between each of the diaphragms and an air cap associated with each diaphragm. As pressurized air is being pumped into the air chamber associated with one diaphragm, the air chamber associated with the other diaphragm is evacuated so that the diaphragms work together in a reciprocating motion to pump a fluid through the pump.
In conventional double-diaphragm pumps, a main valve (typically a spool valve) controls the filling and emptying of the air chambers. The spool valve typically moves back and forth along its axis, connecting and blocking various channels through the pump to control the flow of pressurized air. Typically, a pilot valve associated with the main valve is used to start the main valve moving in one direction or another. The pilot valve is used to help “kick” the main valve back and forth.